Safe search habits when you are working on public Wi-Fi

Public networks are not uniformly risky, and treating them as uniformly risky leads to advice nobody follows. The useful approach is to sort what you are about to do into tiers and let the network decide which tier is allowed. Reading a menu on cafe wifi is fine. Changing the recovery email on your main account from a hotel lobby, on a machine you do not own, is a different act entirely and deserves a different network.

Decide what the network is allowed to carry

Keep three tiers in your head. Browsing and local search, which involves nothing you would mind a stranger seeing, is fine anywhere. Signed-in routine use, such as reading messages or checking a booking, is acceptable on a network you have a reason to trust, meaning one belonging to a place you can name. Anything that changes credentials or moves money belongs on your own mobile connection, and switching to tethering for those two minutes costs almost nothing.

The tier that catches people is uploading. Feeding a scanned identity document or a signed contract into a web tool while on a shared network combines two separate risks in one action, and the file is the part you cannot take back. If it has to happen away from home, tether first, and prefer software already installed on your machine over a page you found while sitting there.

Watch for the network that is pretending

Captive portals are the weak spot, because you have been trained to accept whatever the login page says in order to get online. Before typing anything, check the network name against a sign at the venue or ask, since a duplicate name with a slightly different spelling is trivial to set up and looks identical in the list. Never enter a password you use elsewhere into a portal, and be suspicious of any portal asking for personal detail beyond an email or a room number.

If your browser complains about a certificate while you are on a public network, stop rather than clicking through. On a home connection that warning is usually a misconfigured site; on shared wifi it is the one signal you get that something is sitting between you and the destination. Close the tab, disconnect, and do the task on cellular. This is the single case where the scary dialog deserves to be obeyed.

Assume the screen is public too

Shoulder surfing is unglamorous and it works. In a cafe, a train, or a shared workspace, the person behind you sees your screen for as long as they care to look, and search suggestions and autofill entries reveal things you never typed on purpose. Turn the screen away from the room where you can, and be aware that typing an address into a search field can surface a saved history entry to anyone watching.

Notifications are the other leak. A banner previewing a message, a verification code, or an email subject line appears whether or not you are looking, and in a crowded space that is a broadcast. If you work in public regularly, set previews to hide content while locked and for the apps that carry anything sensitive.

Leave nothing behind on a machine you do not own

On a borrowed or public computer, plan the exit before you start. Work in a private window so history and cookies go away when you close it, and note that a private window does not clean up downloads. Anything you saved is still sitting in the downloads folder under a descriptive filename, so delete the file and clear the download entry, then empty the trash on that machine.

Sign out explicitly rather than closing the tab, since a closed tab often leaves the session alive for whoever sits down next. Check whether the browser offered to save a password and decline or remove it. If you printed something, confirm the job actually printed and did not stay queued on a shared printer with your document name visible in the list.

Before you commit

• Avoid uploading sensitive documents
• Use trusted networks for account changes
• Clear shared-browser downloads when finished

Sort the task into a tier, verify the network name before the portal, keep the screen and the notifications to yourself, and clean up deliberately on hardware you do not own. None of this makes public wifi dangerous to use for ordinary browsing. It just keeps the handful of actions with real consequences off networks you cannot vouch for.